The present invention broadly relates to locking devices that are adapted to secure objects together. More particularly, the present invention concerns key operable locking devices. Specifically, the present invention is directed to size adjustable locking shackles and shanks for such locking devices that, for example, may be used for towage applications, bicycles and the like.
Over the years, there have been numerous variations of locking devices for a multitude of applications. Typically, a locking device is used to secure objects together, whether it be two independent items, a door for an enclosure, or the like. Moreover, a wide variety of locking mechanisms have been employed, including key actuated locks and combination locks, all of various constructions.
A widely used locking device is known as a padlock. The prior art padlock works adequately for a number of conventional applications wherein the span of objects to be secured is relatively short or where the span can be fitted with a hasp. However, numerous shortcomings of padlocks become apparent when a padlock is sought to be used in applications wherein two objects of thick cross-sections are to be secured. Examples of such conventional applications include those where telescopically joined round or square tubing members need to be secured together. Another example is where perpendicular or axially cross-bolting of gates and doors require a substantially rod-like locking device.
As a result of the need for rod or elongated shackle locking devices, various devices have been developed to penetrate multiple surfaces having aligned through bores for the purpose of securing those objects together. Once such example is found in U.S. Pat. No. 2,677,261 issued May 1954 to Jacobi. In the Jacobi patent, a complex locking device is taught in order to prevent actuation of a refrigerator door handle. Another example of a rod locking device is found in U.S. Pat. No. 4,576,021 issued Mar. 18, 1986 to Holden. Holden discloses a locking rod device having a rectangular locking head that is somewhat bulky and non-symmetrical. In the Holden locking device, a radially extendable locking pin engages a circumferential opening in the latch portion of the shackle in order to retain the shackle and locking head together. The bulky nature of this lock head design, however, makes it disadvantageous in use where only limited space is available.
Several additional types of straight shackle locks have been developed wherein the latched portion of the shackle is threadably received in a screw-type lock. Examples of these locks are described in U.S. Pat. No. 4,619,122 issued Oct. 28, 1986 to Simpson as well as in U.S. Pat. No. 4,711,106 issued Dec. 8, 1987 to Johnson. These types of locks, however, tend to be inconvenient and cumbersome to use due to the threaded nature of their locked mechanisms. Specifically, the key actuable locking head described in these two patents require a large number of key rotations in order to thread and fully secure the locking head portion onto the straight shackle. The inconvenience and difficulty of threaded lock systems is compounded when the lock is located in tight or difficult to access areas. Further, the threaded screw lock is especially prone to corrosion and seizure due to the small dimensioning of the threads.
Accordingly, there remains a need for improved locking structures of a rod or cable type nature that can effectively lock objects together. There is a need for such locking mechanisms to have suitable seals and protective structures to prevent ingress of unwanted substances, such as dirt and moisture, into the locking mechanism. There is a further need for locking structures that reduce the tendency for false locking conditions. These conditions are particularly true in the case of trailer hitch locks that utilize linear pins or shanks to connect a draw bar to the trailer hitch receiver inasmuch as these types of hitch locks are continuously exposed to dirt, soil, road grime and the like.
Consequently, my prior U.S. patent application referenced above is designed to meet the aforementioned situations and problems. However, as in the case of trailer hitch units and locks, there are a number of different size units available on the market depending on the size of the rig being towed. Moreover, there are numerous other lock applications which utilize linear pin and shank locks that incorporate shanks having different diameter sizes for different situations. As a result, a number of different locking devices having different sized shanks are needed to meet varied particular applications. This is cumbersome and expensive. Therefore, there is a need for a locking mechanism using a linear shank that is convertible for various applications. In this manner, a single locking unit may be used for a number of varied size locking requirements, such as where the apertures in the units to be connected and locked are varied from application to application.
It is an object of the present invention to provide a new and useful locking device that is simple in construction yet which provides a strong mechanical construction.
It is another object of the present invention to provide a locking structure which is convertible for use with different sized connecting openings.
It is yet another object of the present invention to provide a convertible locking structure which is adaptable in size for different connection openings.
Still another object of the invention is to provide variable mechanisms for maintaining the convertible state of the locking structure once it is selected.
A further object of the present invention is to provide a bolt-type locking structure having a pleasing, symmetrical appearance.
According to the present invention, then, a locking device is provided which is adapted to secure objects together. In its broad form, this locking device includes a shackle member having a shank terminating in first and second end portions. The shank is preferably linear. A latch portion is disposed at the shank first end portion and is configured to selectively engage a locking member. A stop portion is disposed at the shank second end portion. Finally, a sleeve is configured for selective engagement on the linear shank to vary the thickness dimension thereof. The locking device may in one preferred form be constructed to include a retaining member for selectively securing the sleeve in position on the shank.
In one preferred structure, the sleeve includes a plurality of sleeve elements each having a common inner diameter sized for mounting on the shank and each with a different outer diameter. Preferably, the sleeve includes three of such sleeve elements with each having a different outer diameter varying between xe2x85x9c inch to xc2xd inch.
In another preferred structure, the sleeve includes a plurality of sleeve elements having variable outer diameters and configured to be selectively nested within each other. The innermost sleeve element of the nested sleeve elements is sized for mounting on the shank. In a preferred structure, the plurality of sleeve elements is in the form of three of such nested sleeve elements wherein a first sleeve element is sized for fitting onto the shank, the second sleeve element is sized for fitting onto the first sleeve element, and the third sleeve element is sized for fitting onto the second sleeve element.
In another preferred structure, the shank first end portion includes an annular groove therein proximate to the latch portion. The retaining member is in the form of a retention element configured for selective positioning within this annular groove to maintain the sleeve in position on the shank. This retaining element may take several constructions. In one form, the retention element is an annular O-ring disposed in said annular groove. In another form, the retention element is a C-shaped washer that has facing arm ends that define a gap therebetween for selective positioning in the annular groove.
In yet another preferred structure, the retaining member is in the form of a first set of threaded elements disposed on one end of the sleeve which are configured for threaded engagement with the stop portion. To accommodate this, it is preferred that the stop portion include an end portion which has a second set of threaded elements disposed therein and which are configured to receive and engage the first set of threaded elements disposed on the sleeve. Finally, the sleeve and the shank may have a common linear length between the stop portion and the latch portion.